Consequences of an Abelian $Z'$ for neutrino oscillations and dark matter

TL;DR

This paper explores how an Abelian $Z'$ gauge symmetry impacts neutrino oscillations and dark matter, analyzing various symmetry scenarios and their compatibility with observed neutrino data and dark matter production.

Contribution

It systematically studies the implications of gauging different anomaly-free symmetries with minimal matter content for neutrino phenomenology and dark matter, identifying which models are viable.

Findings

Most symmetries require additional matter for neutrino data compatibility.

A non-thermal dark matter scenario involving $Z'$ decay is compatible with certain symmetries.

Sterile neutrino dark matter likely contributes minimally to neutrino masses.

Abstract

The Standard Model's accidental and anomaly-free currents: $B-L$, $L_e-L_\mu$, $L_e-L_\tau$, and $L_\mu-L_\tau$, could be indicative of a hidden gauge structure beyond the Standard Model. Additionally, neutrino masses can be generated by a dimension-5 operator that generically breaks all of these symmetries. It is therefore important to investigate the compatibility of a gauged $U'(1)$ and neutrino phenomenology. We consider gauging each of the symmetries above with a minimal extended matter content. This includes the $Z'$, an order parameter to break the $U'(1)$, and three right-handed neutrinos. We find all but $B-L$ require additional matter content to explain the measured neutrino oscillation parameters. We also discuss the compatibility of the measured neutrino textures with a non-thermal dark matter production mechanism involving the decay of the $Z'$. Finally, we present a parametric relation that implies that a sterile neutrino dark matter candidate should not be expected to contribute to neutrino masses beyond ten parts per million.